Centrally acting emetics. 10. Rigid dopamine congeners derived from octahydrobenzo[f]quinoline

In a study of conformational requirements for certain dopaminergic agonist molecules, a series of conformationally predictable dopamine congeners related to cis- and trans-octahydrobenzo[f]quinoline was prepared. The complexity and equivocal character of the reduction of variously substituted 4-methyl-1,2,3,4,5,6-hexahydrobenzo[f]quinolines were demonstrated and studied. It was shown that several literature methods for reduction of these systems were in error regarding the stereochemical nature of the product(s). It has been concluded that geometrically specific and predictable reductions of these hexahydrobenzo[f]quinolines seem unlikely to attain, and a plausible rationalization for this conclusion has been proposed. Pharmacologic data on the compounds prepared are consistent with our earlier proposals of a biologically significant conformation of dopamine for emesis, the pecking syndrome in pigeons, and other physiological effects.